Maryland Gov. Larry Hogan declared a state of emergency in Howard County on Sunday after six inches of rain fell in two hours on Saturday night, causing the Patapsco River to gush through streets. A 35-year-old woman and 38-year-old man were killed, Baltimore County police said.

"That human chain [video] has gone around the world five or six times already," he said. "People know that whenever people in a community would do that for their neighbors, or even for strangers, they will not let this storm defeat us."